What writing is on the card. Is there a version number?
Suggestion: Set it to 1.3 (boot). Set the SCSI jumper to 6. Try it. Also verify what SCSI ID your physical drive has. All SCSI drives have a jumper pads for setting the ID.
Most SCSI cards default to ID7. So, drives are setup as ID 0 thru 6. The SCSI bus reads from 6 to 0, so 6 is preferred for physical hard drives.
There maybe a problem with the card set to 6 and the drive set to 6, as this would be technically wrong. It should cause all types of havoc, and lockup the bus with the symptoms you said.